Injured and bleeding, mothers carrying infants fled from a maternity hospital shattered by a powerful gas explosion on Thursday, and rescuers swung sledgehammers to break through fallen concrete in hunt for others who may have been trapped.
Three people were killed and at least 65 others were injured, authorities said, NBC News reported. Officials earlier told The Associated Press that four had been killed.
Thirty-five-year-old Felicitas Hernandez wept as she frantically questioned people outside the mostly collapsed building, hoping for word of her month-old baby, who had been hospitalized since birth with respiratory problems.
"They wouldn't let me sleep with him," said Hernandez, who said she had come to the city-run Maternity and Children's Hospital of Cuajimalpa because she had no money.
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The explosion occurred when the tanker was making a routine, early morning delivery of gas to the hospital kitchen and gas started to leak. Witnesses said the tanker workers struggled frantically for 15 or 20 minutes to repair the leak while a large cloud of gas formed.
"The hose broke. The two gas workers tried to stop it, but they were very nervous. They yelled for people to get out," said Laura Diaz Pacheco, a laboratory technician.
"Everyone's initial reaction was to go inside, away from the gas," she added. "Maybe as many as 10 of us were able to get out ... The rest stayed inside."
Workers on the truck yelled: "Call the firefighters, call the firefighters!" said 66-year-old anesthesiologist Agustin Herrera. People started to evacuate the hospital, and then came the massive explosion that sent up an enormous fireball and plumes of dust and smoke.
Herrera saw injured mothers walking out carrying babies. He said there had been nine babies in the 35-bed hospital's nursery, one in very serious condition before the explosion.
"We avoided a much bigger tragedy because the oxygen tanks are right beside (the area) and they didn't explode," Herrera said. The most affected parts of the hospital were the neonatology, reception and emergency reception units, he added.
Miguel Angel Garcia, smoked a cigarette outside Hospital ABC-Santa Fe, trying to calm his nerves while he waited to see his wife and new baby daughter, who had been moved there.
Garcia, 22, had been driving a bus when he heard about the explosion at the hospital where his wife had given birth to their second child just the day before. He dropped off his passengers, then his bus and took off for the hospital.
"When I arrived and saw it in pieces, I thought the worst," Garcia said. He waited for an hour before authorities told him his wife and daughter had been taken to the Santa Fe hospital. A nurse there told him both were fine, but he hadn't been allowed to see them yet.
As the day wore on, people arrived to offer diapers and baby formula. There was an hour-long wait to donate blood.
The driver and two employees were hospitalized but are also in custody, said a Mexico City government spokesman, who could not be named because she was not authorized to speak to the press.
Mayor Miguel Angel Mancera earlier told the Televisa network that at least 54 people were injured, 22 of them children. Most of the injuries were relatively minor, he said, many caused by flying glass.
The explosion sent a column of smoke billowing over the area on the western edge of Mexico's capital and television images showed much of the hospital collapsed, with firefighters trying to extinguish fires.
"The truck must have had some failure, the hose and that's what caused the explosion," Mancera said. He said that fire continued burning because firefighters recommended that they allow the truck's remaining gas to burn off. He said there was no risk of another explosion.
Ismael Garcia, 27, who lives a block from the hospital, said "there was a super explosion and everything caught on fire."
Garcia ran to the hospital and said he and others made their way to the nursery. "Fortunately, we were able to get eight babies out," he said.
Rafael Gonzalez of the Red Cross said one 27-year-old man arrived at the agency's hospital with burns over 90 percent of his body, and he was transferred to another hospital.
President Enrique Pena Nieto expressed his sadness and support for the victims through his official Twitter account.
The hospital, located in a middle class neighborhood, is next to a school.